Diffusion effects under low flow conditions.

Details

• Personal Author:
  Heitbrink, William A.
• Description:
  Low and high flow rate personal sampling pumps were compared for diffusion effects. Tests were run to determine at what flow rate positive bias occurs as a result of diffusive mass influx at the solid sorbent tube sampling train inlet. Two mathematical models predicted the flow rate at which diffusive flux is a bias. Less than 3.0 cubic centimeters per minute (cc/min) and 1.5cc/min were the flow rates where bias was predicted. To test these mathematical models, experimental tests were performed. Two sets of ethanol (64175) samples were collected on charcoal tubes, one set at monitored ethanol concentration in the test manifold. To measure volumetric flow rates, the rate of pressure increase was determined using a transducer and valving. Ethanol samples were taken and analyzed by gas chromatography. Analysis of samples collected at flow rates of 0.8cc/min showed concentrations as much as 75 percent higher than from samples collected at flow rates of 20cc/min. The author concludes that diffusive flux can be a bias at low sampling. [Description provided by NIOSH]
• Subjects:
  Atmosphere Environmental Monitoring Manufacturing And Industrial Facilities Occupational Health Safety
• Keywords:
  Air-monitoring Air-sampling-techniques Analytical-methods Atmosphere-analyzers Diffusion-analysis Industrial-environment Industrial-hygiene Monitoring-systems NIOSH-Author Sandblasting
• ISSN:
  0002-8894
• Document Type:
  Text
• Genre:
  Journal Article
• Place as Subject:
  Ohio ; OSHA Region 5
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  DPSE - Division of Physical Sciences and Engineering
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  453-462
• Volume:
  44
• Issue:
  6
• NIOSHTIC Number:
  nn:00137305
• Citation:
  Am Ind Hyg Assoc J 1983; 44(6):453-462
• Contact Point Address:
  William A. Heitbrink, U.S. Department of Health & Human Services, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety & Health, 4676 Columbia Parkway, Cincinnati, OH 45226
• CAS Registry Number:
  Ethanol (CAS RN 64-17-5)
• Federal Fiscal Year:
  1983
• Peer Reviewed:
  True
• Source Full Name:
  American Industrial Hygiene Association Journal
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:6f61a6474f637d83d112bc05fb475c37c3abdcdb5d2fa55d7a99ccbb9695a08a6b4682efbd4116e85712411cd0d32e8b1978d87208f1c982f1c0f0567eb4aa06
• Download URL:
  https://stacks.cdc.gov/view/cdc/184705/cdc_184705_DS1.pdf
• File Type:
  [PDF - 861.46 KB ]